MDAC 2.5 SDK - OLE DB Programmer's Reference
Chapter 1: Overview of OLE DB
Today, a vast amount of critical information necessary to conduct day-to-day business is found outside of traditional, corporate production databases. Instead, this information is found in file systems, in indexed-sequential files such as Btrieve, and in personal databases such as Microsoft® Access and Microsoft Visual FoxPro®; in productivity tools such as spreadsheets, project management planners, and electronic mail; and on the World Wide Web. To take advantage of the benefits of database technology, such as declarative queries, transactions, and security, businesses have traditionally had to move the data from its original containing system into a database management system (DBMS).
This process is expensive and redundant. Furthermore, businesses need to be able to exploit the advantages of database technology not only when accessing data within a DBMS but also when accessing data from any other information container. To address this need, Microsoft created OLE DB.
OLE DB is a set of Component Object Model (COM) interfaces that provide applications with uniform access to data stored in diverse information sources and that also provide the ability to implement additional database services. These interfaces support the amount of DBMS functionality appropriate to the data store, enabling it to share its data.